1. Field of the Invention
This invention relates to generally a rooftop grease containment apparatus.
2. Description of the Prior Art
Since practically from the time cooking began, humans have recognized the importance of removing hot air and grease from the cooking area. As early as 1924, M. E. Koehler in U.S. Pat. No. 1,509,674, obtained patent protection for a simple vent apparatus used to purify greasy or sooty smoke and vapors arising from a kitchen range. By 1929, L. W. Ray in U.S. Pat. No. 1,732,315, recognized that the addition of an exhaust fan would improve the efficiency of the vent. By 1957, driven by the proliferation of fast food and drive-ins and the kitchen ranges used therein, E. Graswich, attempted in U.S. Pat. No. 2,793,712 to improve grease efficiency removal through an increase in the surface area within the vent system.
While over the years, many improvements such as those described in U.S. Pat. No. 7,537,642 (Damrath), U.S. Pat. No.7,484,506 (Besal), U.S. Pat. No.7,332,004 (Jackson), U.S. Pat. No. 6,050,258 (Neitzel), U.S. Pat. No. 5,472,342 (Welsh), U.S. Pat. No. 5,020,511 (Liu), and U.S. Pat. No. 4,506,655 (Kuechler) have been made to the simple vent apparatus of Koehler, the basic method has remained the same, that being a vent pipe generally located directly above the cooking surface, through which the heated air entrained with grease (or other contaminants) flows, sometimes with the assistance of an exhaust fan, to the roof of a building and exits to the surrounding atmosphere. As the grease entrained air travels up through the vent pipe, some grease becomes deposited upon the inner surfaces of the vent pipe. Any grease that exited the vent pipe into the ambient air would then, as a result of gravity, fall back and be deposited on the roof surfaces surrounding the vent. What was not appreciated in these earlier patents was the fact that grease accumulating on a roof posed a fire danger, could destroy the roof surfaces, and was extremely slippery when walked upon.
Beginning with the 1989 patent entitled “Apparatus for Collecting and Storing Grease Discharged from Roof Mounted Exhaust Systems”, U.S. Pat. No. 4,869,236, issued to Blough, a method was disclosed for a way accumulate the grease exiting the vent into canisters. The concept of collecting grease through use of some form of cannister was subsequently utilized in U.S. Pat. No. 6,648,937 (Nguyen), U.S. Pat. No. 6,010,558 (Ackland), and U.S. Pat. No.4,987,882 (Kaufman). In U.S. Pat. No. 6,716,099, issued to Pfleiderer and U.S. Pat. No. 6,676,723 issued to Chwala, a method for accumulating grease in a catch basin built around the roof vent was disclosed. In order to increase the efficiency at which grease is removed from the hot air before such air exits the vent, other inventions patented during this time period such as US Patent Publication Number 2009/0301305 (Gaddy), and U.S. Pat. No. 5,814,115 (Allen) attempted to increase the surface area available for grease deposition by the utilization of a filter designed to filter out and collect the grease before the air exited the vent pipe.
In all of these patents, the efficiency of the vent system was limited by two interrelated factors, the speed of the air flowing through the vent and the efficiency at which grease is removed from the hot air before such air exits the vent. One way to increase the velocity of the air through the vent would be to increase the speed at which the exhaust fan rotates, however at some point the size of the fan desired would be cost prohibitive as well as structurally not supportable. One way to increase the efficiency at which grease is remove from the hot air before such air exits the vent is by use of a filter, however, filters are an impediment to air flow, must be periodically cleaned and/or replaced otherwise they will become clogged and, even when clean, will not eliminate all grease from exiting the vent. The most effective way to both increase the velocity of the air traveling through the vent while simultaneously improving the efficiency at which grease is removed from the air before such air exits the vent, is through the novel use of a vertical separator.
One only has to look at the roof of any restaurant to see, at least the roof portion, of any typical vent system. What one will see is a small length of duct work exiting the roof at the top of which is domed cover. Sometimes the domed cover may include the exhaust fan and/or any of the grease collection methods disclosed in the US patents discussed above. There are literally thousands if not hundreds of thousands of these types of vent installations throughout the United States. In order to be cost effective, any novel grease collection method such as that described in this patent application, must be able to be retrofitted to the existing vent systems.